Presently, carpet is used routinely in residential, commercial, industrial, and automobile settings. Although many types of styles and colors are available, the face fibers of carpets produced in North America are predominantly comprised of nylon 6, produced by Allied-Signal Corporation, or nylon 6,6 produced by Solutia Corporation. In addition to the face fiber, which is about 50% by weight of a carpet, a typical broadloom carpet also contains about 10% by weight polypropylene primary and secondary backings, about 9% by weight styrene-butadiene rubber (SBR) latex adhesive, and about 35% by weight calcium carbonate as filler. The construction of a typical broadloom carpet involves weaving the face fiber through the primary polypropylene backing forming a "U" shaped fiber such that the ends of the face fiber form the pile of the carpet, i.e., the surface of the carpet, and the base of the "U" shaped fiber is located beneath the primary polypropylene backing. A layer of a composition comprising the SBR latex adhesive and calcium carbonate filler is then applied to the surface of the primary polypropylene backing opposite of the pile such that the base of the "U" shaped fiber is embedded in the composition. A secondary backing made of polypropylene is then adhered to the layer comprising SBR latex adhesive and calcium carbonate opposite to the pile. A schematical cross sectional view of a typical broadloom carpet is set forth in FIG. 1.
In order to produce the huge amounts of carpet consumed by the construction industry, and to replace worn carpet, billions of pounds of fibers are produced. For example, in 1995, Canada and the United States produced 3.1 billion pounds of fiber for carpets. With these fibers, approximately 6.4 billion pounds of carpet were produced, of which about 70% was used to replace worn carpet. In order to decrease the amount of landfill volume used by disposed carpet, and to recycle valuable components of carpet, such as the face fibers, efforts have been made to isolate and depolymerize nylon 6 face fibers from carpet. A particular example of such a method is set forth in U.S. Pat. No. 5,457,197 (the '197 patent) and U.S. Pat. No. 5,681,952 (the '952 patent), both of which are hereby incorporated by the reference herein in their entireties. The '197 patent discloses a process for recovering monomer from a multi-component polymeric waste material, such as carpet, that includes at least one hydrolyzable polymeric component, e.g., the nylon 6 pile. As a result of the processes set forth in these patents, nylon 6 fibers can be removed from a multicomponent carpet and depolymerized to form caprolactam, while the remaining components of the carpet form a calcium carbonate and thermoplastic resin blend referred to as "Q compound". Q compound is a black, brittle solid made up of non-nylon 6 components of carpet produced with the processes of the '197 and '952 patents. In particular, Q compound comprises by weight about 63-65% calcium carbonate, about 15-18% polypropylene, and about 12-15% styrene butadiene rubber. Since carpets processed pursuant to the teachings of the '197 and '952 patents are generally constructed in the same manner with the same materials, the Q compound produced using these processes generally has the same composition and physical properties. Table 1 sets forth ranges and average of the calorific value, and amounts of sulfur and chloride found in Q compound.
TABLE 1 Range and Average Parameters regarding properties of Q Compound Parameter Measuring Method Range Average BTU/lb ASTM D-2015-85 6660-6914 6818 % Sulfur ASTM D-3177 0.19-0.30 0.24 % Chloride ASTM C-114 0.05-0.09 0.07
Furthermore, a Material Safety Data Sheet describing the properties of Q compound is incorporated by reference herein, and attached hereto as "Appendix A".
Since tons of nylon 6 are being reclaimed and recycled every year, tons of Q compound are being produced with no apparent use. Accordingly, what is needed is a use for Q compound so that all the components of discarded carpet can be recycled, thus alleviating the strain on available landfills.
The citation of any reference herein should not be construed as an admission that such reference is available as "Prior Art" to the instant application.